Automatic firearm with breech casing free to recoil on a support



Dec. 3l, 1968 H. HERLACH 3,418,880

AUTOMATIC FIRE/RM WITH BREECH cAsING FREE To RECOIL 0N A SUPPORT Filed July 28. 1966 151 1'7 102 lyezvo/ 27 Blz-1.511;

f l0] 32y 3o 21 s4 31 29 9 L? www Heli? rfc/1 Her/ach By WMM/40%, offndiw 3,418,880 AUTOMATlC FiREARM WITH BREECH CASING FREE T RECIL 0N A SUPPORT Heinrich Herlach, Zurich, Switzerland, assignor to Ocrlikon-lluhrle Holding Ltd., Zurich, Switzerland Filed July 28, 1966, Ser. No. 568,430 Claims priority, application Switzerland, `luly 29, 1965, 10,699/65 4 Claims. (Cl. 89-42) ABSTRACT 0F THE DISCLOSURE An automatic firearm wherein two elements, a support and a breech casing, are provided. The breech casing is mounted free to recoil on the support. A hydraulic damping device is provided for damping the run forward of the -breech casing. The damping device has a first and a second part such as respectively a cylinder and a piston. A springloaded valve is open during the recoil of the breech casing for making the damping device ineffective during the recoil of the breech casing. The first part is connected fixedly with one of the two elements and the second part is movable relative to the other of said two elements. An elastic buffer element is provided for braking the forward run of the breech casing and damping the movement of the second part relative to the other element, and a recuperator spring damps the recoil of said breech casing.

This invention relates to an automatic firearm with a breech casing mounted free to -recoil on a support and a damping device acting between the breech casing and the support, which is provided with a hydraulic brake acting during the run forward of the :breech casing to a rest position, and an elastic lbuffer element absorbing the run forward of the breech casing.

Weapons of this kind are known, and which the hydraulic Ibrake and elastic buffer element work in parallel and wherein the forward-running breech casing is checked by the buffer element on over-running its rest position. If, with such a weapon7 an axially slidable breech block were to be mounted in the breech casing, then this breech block would impinge against the breech casing at the end of its forward run, whereby the latter would undergo a sudden increase in velocity from the impact. In spite of the existence of the buffer element, a disadvantageous transmission of the impact to the support would occur, as during the impact the force exerted by the hydraulic brake is at its maximum so that, as a result of the parallel connection mentioned, the buffer element cannot yield. These impacts, repeatedly exerted on the support or the mounting during a burst of lire, would result in a reduction in the accuracy of fire of the gun.

The invention has the object of damping the transmission of these shocks from the breech casing to the support. In accordance with the invention, the buffer element is arranged in series with the hydraulic brake and damps the transmission to the support of the shock which occurs on impact against the @breech casing of a breech block running forward in the breech casing.

In the case of a device of the type mentioned above in which the lbreech casing has a rest position, in accordance with the invention, the checking of the breech casing on over-running the rest position is attained by determining the rest position of a part of the hydraulic brake in driving connection with the breech casing, through contact of the part with a second part of the hydraulic brake secured to the support by the action of the buffer element. Thereby the additional advantage is obtained that no special lbuffer element is required for nited States Patent O 3,418,880 Patented Dec. 31, 1968 ICC checking the breech casing on over-running the rest position, since this function is also taken over by the buffer element arranged in accordance with the invention.

With the above and other objects in view which will become apparent from the detailed description below, a preferred embodiment of the invention is shown in the drawings in which:

FIGURE 1 is a partial diagrammatic side view of an automatic firearm mounted on a support with a damping device.

FIGURE 2 is an enlarged partial cross-sectional view showing in longitudinal section one position of the damping device in the -rest position.

FIGURE 3 is a similar view of the damping device showing the position of the elements during the recoil of the weapon, and

FIGURE 4 is a similar view showing the position of the elements after the transmission of an impact through the hydraulic brake.

A firearm is shown in FIGURE 1 similar to that described in Patent No. 2,536,997. The automatic firearm 12 is slidably supported in the slides 11 of the cradle 10 connected to the gun support, the breech block 13 of which is, after a shot, thrown against the plunger 14 of the hydraulic spring 16 serving as a buffer, and moved `forward again by the latter in conjunction with the return spring (not shown in the drawing) also compressed during the recoil of the breech block. The damping device comprises a hydraulic brake 17, the cylinder casing 18 of which is slida-bly supported in the supports 102 connected to the cradle 10 and a recuperator spring 19 supported on the one hand on the casing 18 and on the other hand on a rib 101 of the cradle 10.

As can be seen from FIG. 2, the cylinder casing 18 of the brake 17 is in driving connection `with the breech casing 15 of the weapon 12, as a cam 151 of the breech casing is secured to the cylinder casing 18 by a locking catch 20. A piston 21 is supported in cylinder casing `18, which is rigidly connected to a piston rod 22, which extends through the Whole cylinder casing 18 and pr0- jects from it at both ends. The openings for the piston rod 22 in the casing ends 181, 182 are sealed with rings 23. Over the rear end of the piston Irod 22, projecting through an orifice in the rib 101 connected to the cradle 10, a sleeve 2S is slid. This sleeve 25 is compressed against the rod shoulder 221 by a nut 24. A buffer spring 27, made up from a set of cup springs 28, is clamped between the flange 26 connected to the sleeve 25 and the rib 101. Through the initial stress of the buffer spring 27, which is so selected that it is not actuated by the maximum compression of the recuperator spring 19', the shoulder 251 of the sleeve 25 is pulled against the ri-b 101 and thereby determines the rest position of the piston rod 22.. Through the recuperator spring 19 abutting against the rear end 132 of the cylinder casing 18, the cylinder casing is pressed against a shoulder 222 of the piston rod 22, whereby the rest position is determined of the breech casing 15, in driving connection with the casing 13.

The piston rod 22 has a central hole 29, which is formed from the end not supported on the cradle 10, and into which lead two holes 30, 31 running at right angles to the longitudinal axis. These two transverse holes 30, 31 lie on each side of the piston 21. By adjusting the control member 32, screwable into the end of the piston rod, the cross section of the orifice of the front transverse hole 3), and thereby the braking force acting on the cylinder casing, can be altered. The piston 21 has axial holes 33, which, in the stationary condition, are kept closed by spring-loaded valvesV 34 arranged on its rear face. The overall diameter of the piston 21 is somewhat less than the inside diameter of the cylinder casing 18, so that the piston circumference is bounded by a small annular-shaped cross-section 35.

The mode of operation with the construction described is as follows:

The breech block 13 of the weapon 12 is held back by the catch hook of the trigger device in the hooked-back position shown in dot and dash lines. After release, the breech block 13 runs forward and strikes against the breech casing 15. This position, called the return forward of the breech block 13, is shown dotted in FIGURE l. The breech casing 15, together with the cylinder casing 18 of the hydraulic brake 17 driven by it and the piston rod 22 resting against it, are accelerated forward by this impact, whereby the kinetic energy of all these parts mentioned is transmitted by the piston rod 22 to the resilient buffer spring 27. At the moment of impact of the breech block the propellant charge of the cartridge fed by it into the chamber is ignited. The breech block 13, for a brief period of time locked to the breech casing 15, under the pressure of the gas-pressure loaded cartridge case imparts a rearward impulse to the breech casing 15 (still running forward), so that the latter comes to a standstill and is then thrown back against the pressure of the recuperator spring 19. After the piston rod 22, moving to the rear together with the breech casing 15 under the action of the buifer spring 27, has again .attained the rest position, indicated by the contact of the sleeve 25 connected to it with the rib 1, the breech casing 15, recoiling further, is -carrying out a movement in relation to the piston rod 22. Thereby a portion of the fluid located in front of the piston 21 is forced into the portion of the cylinder 18 bounded by the rear side of the piston 21, through the annularshaped cross-section 35, through the holes 30, 29 and 31 of the piston rod 22 and furthermore through the holes 33 in the piston 21, the valves of which open under the pressure of the fluid (FIGURE 3).

On the forward movement of the breech casing and cylinder casing 18 started by the pressure of the recuperator spring 19, Huid is again forced from the rear side of the piston 21 through the cross-section 35 and the holes 31, 29, 30 into the portion of the cylinder casing 18 bounded by the front side of the piston. Under the pressure of the fluid, the valves 34 remain closed. The total cross-section of the orifices for the fluid is thus considerably reduced in comparison to conditions existing during the recoil of the weapon, so that a much greater braking force now acts on the cylinder casing 18, and thereby on the breech casing 15.

After the impact on the buffer 16, the breech block 13 is moved forward again and during the run forward of the breech casing 15 again strikes it. Through this impact, if it takes place still a certain distance behind the rest position, the breech casing 15, tand therewith the cylinder casing 18, undergo a sudden increase in velocity, whereby the portion of the brake tiuid located behind the piston 21 is suddenly accelerated. This fluid mass, acting like a solid at the moment of impact, now suddenly accelerates forward the piston 21 and the piston rod 22, so that the shoulder 251 of the sleeve 25 moves away from the stop on the rib 101 (FIGURE 4). The shock thereby exerted on the piston rod 22 is attenuated by the buffer spring 27 on the rib 101 and therewith transmitted to the cradle 101. The damping of this shock prevents it setting up a vibration in the cradle 10 and the remainder of the mounting such as could affect unfavorably the accuracy of the second shot occurring immediately .after the impact of the breech on the breech casing 15. Under the action of the buffer spring 27, the piston rod 22 at once moves back to the rest position. After the occurrence of the second shot, the breech casing 15 is braked to a standstill, whereupon the phenomena of movement of the breech block casing 15, breech 13 and hydraulic brake 17, in force after the occurrence of the iirst shot, repeat and, of course, also after each succeeding shot.

In the exemplified embodiment of the subject of the invention described in the foregoing, the buffer spring 27 acts between the hydraulic brake 17 and the support 10. It also, of course, remains a subject of the invention if the buffer element between the breech casing 15 and the hydraulic brake 17 acts to damp the transmission of the shocks from the breech casing 15 to the support 10. In

. this case, which is not depicted, the breech casing 15 is,

for example, provided with .a ring in which the hydraulic brake is supported free to move and against which both the recuperator spring and the 'buffer spring are Supported. The further supporting of the springs is on ring anges, which are fixed on each side of the ring mentioned on the hydraulic brake 17. The piston rod 22 is in this case rigidly connected to the support 10. In other respects the construction can be as in the example previously described.

I claim:

1. Automatic firearm comprising two elements, said elements being a support and a breech casing, said breech casing being mounted free to recoil on said support, a hydraulic damping device for damping the forward run of said breech casing including a first part and a second part, said parts being respectively a cylinder and .a piston, said damping device comprising a spring-loaded valve open during the recoil of said breech casing for making said damping device ineffective during the recoil of said breech casing, said first part being connected fixedly with one of said two elements .and said second part being movable relative to the other of said two elements, an elastic buffer element for braking the forward run of said breech casing, said buffer element damping the movement of said second part relative to said other element, and a recuperator spring for damping the recoil of said breech casing.

2. An automatic lirearm as set forth in claim 1 wherein said buffer element is a cup spring.

3. An automatic rearm as set forth in claim 1 wherein said buffer element is located between said support and said piston.

4. An automatic rearm as set forth in claim 1 wherein a stop is provided on said piston so that said recuperator spring urges said cylinder against said stop to a rest position of said cylinder against said stop.

References Cited UNITED STATES PATENTS 1,373,103 3/1921 Schneider 89-43 2,186,969 1/1940 Green. 2,273,878 2/1942 Magrum et al. 2,293,069 8/1942 McNeill et al. 2,735,670 2/ 1956 Schultze 89-42 X 3,033,384 5/1962 Zanow et al. 3,082,667 3/1963 Ramseger 89-43 X BENJAMIN A. BORCHELT, Primary Examiner.

S. C. BENTLEY, Assistant Examiner.

U.S. Cl. X.R. 18S-86; 267-1 

